What is MS-DOS?

MS DOS is the abbreviation for Microsoft Disk Operating System. Microsoft Corporation manufactures MS-DOS. A disk operating system does just what its name suggests-controls disk commands.


Computers speak a different language than us. They think exclusively in numbers. Actually, they think in zeros and ones, or in the binary system. People could probably think in binary, but we need an interface or bridge that allows the computer to understand the user.

This interface should allow the user to enter commands in English form that the computer can execute. These commands are actually short programs which the computer executes in its own way.

In short, MS-DOS was an operating system. This operating system gives the computer basic instructions about disk and file management, and allows communication between the computer and user.

This is what the early DOS could do on Personal Computers

  1. Controlling Input/Output devices.
  2. CPU Scheduling and controlling processes
  3. Memory and File storage management
  4. Handled basic errors
  5. Executing and supervising user applications programs
  6. Provided CLI between user and computer system


MS DOS was the first widely installed operating system on Personal Computers. It was the main compatible operating system on computers that IBM shipped back in 1980’s. At that time Windows was like an ‘app’ that ran on top of MS DOS. It ended up being replaced by Windows because of its GUI.

Now it is the other way round. Windows supports a MS DOS like interface by emulating the same. Microsoft discontinued support for MS DOS on 31st December, 2002. MS DOS was not at all like the multi purpose operating systems we use today. It was a file manager along with a simple program loader


File names were limited to 8 characters with a 3 character extension. The launch of Apple Macintosh which had a GUI in 1984 was probably the first nail in the coffin of DOS. The original DOS was written in Assembly Language.





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